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Theorem infdifsn 9695
Description: Removing a singleton from an infinite set does not change the cardinality of the set. (Contributed by Mario Carneiro, 30-Apr-2015.) (Revised by Mario Carneiro, 16-May-2015.)
Assertion
Ref Expression
infdifsn (ω ≼ 𝐴 → (𝐴 ∖ {𝐵}) ≈ 𝐴)

Proof of Theorem infdifsn
Dummy variable 𝑓 is distinct from all other variables.
StepHypRef Expression
1 brdomi 9024 . . . 4 (ω ≼ 𝐴 → ∃𝑓 𝑓:ω⟶1-1𝐴)
21adantr 486 . . 3 ((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) → ∃𝑓 𝑓:ω⟶1-1𝐴)
3 reldom 9017 . . . . . . 7 Rel ≼
43brrelex2i 5715 . . . . . 6 (ω ≼ 𝐴 → 𝐴 ∈ V)
54ad2antrr 739 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝐴 ∈ V)
6 simplr 781 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝐵 ∈ 𝐴)
7 f1f 6808 . . . . . . 7 (𝑓:ω⟶1-1𝐴 → 𝑓:ω⟶𝐴)
87adantl 487 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝑓:ω⟶𝐴)
9 peano1 7934 . . . . . 6 ∅ ∈ ω
10 ffvelcdm 7113 . . . . . 6 ((𝑓:ω⟶𝐴 ∧ ∅ ∈ ω) → (𝑓‘∅) ∈ 𝐴)
118, 9, 10sylancl 598 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓‘∅) ∈ 𝐴)
12 difsnen 9116 . . . . 5 ((𝐴 ∈ V ∧ 𝐵 ∈ 𝐴 ∧ (𝑓‘∅) ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}))
135, 6, 11, 12syl3anc 1399 . . . 4 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}))
14 vex 3458 . . . . . . . . . 10 𝑓 ∈ V
15 f1f1orn 6866 . . . . . . . . . . 11 (𝑓:ω⟶1-1𝐴 → 𝑓:ω⟶1-1ontoran 𝑓)
1615adantl 487 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝑓:ω⟶1-1ontoran 𝑓)
17 f1oen3g 9031 . . . . . . . . . 10 ((𝑓 ∈ V ∧ 𝑓:ω⟶1-1ontoran 𝑓) → ω ≈ ran 𝑓)
1814, 16, 17sylancr 599 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ω ≈ ran 𝑓)
1918ensymd 9070 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ran 𝑓 ≈ ω)
203brrelex1i 5714 . . . . . . . . . . 11 (ω ≼ 𝐴 → ω ∈ V)
2120ad2antrr 739 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ω ∈ V)
22 limom 7927 . . . . . . . . . . 11 Lim ω
2322limenpsi 9209 . . . . . . . . . 10 (ω ∈ V → ω ≈ (ω ∖ {∅}))
2421, 23syl 18 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ω ≈ (ω ∖ {∅}))
2514resex 6036 . . . . . . . . . . 11 (𝑓 ↾ (ω ∖ {∅})) ∈ V
26 simpr 490 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝑓:ω⟶1-1𝐴)
27 difss 4075 . . . . . . . . . . . 12 (ω ∖ {∅}) ⊆ ω
28 f1ores 6869 . . . . . . . . . . . 12 ((𝑓:ω⟶1-1𝐴 ∧ (ω ∖ {∅}) ⊆ ω) → (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})⟶1-1onto(𝑓 “ (ω ∖ {∅})))
2926, 27, 28sylancl 598 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})⟶1-1onto(𝑓 “ (ω ∖ {∅})))
30 f1oen3g 9031 . . . . . . . . . . 11 (((𝑓 ↾ (ω ∖ {∅})) ∈ V ∧ (𝑓 ↾ (ω ∖ {∅})):(ω ∖ {∅})⟶1-1onto(𝑓 “ (ω ∖ {∅}))) → (ω ∖ {∅}) ≈ (𝑓 “ (ω ∖ {∅})))
3125, 29, 30sylancr 599 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (ω ∖ {∅}) ≈ (𝑓 “ (ω ∖ {∅})))
32 f1orn 6865 . . . . . . . . . . . . 13 (𝑓:ω⟶1-1ontoran 𝑓 ↔ (𝑓 Fn ω ∧ Fun ◡𝑓))
3332simprbi 503 . . . . . . . . . . . 12 (𝑓:ω⟶1-1ontoran 𝑓 → Fun ◡𝑓)
34 imadif 6654 . . . . . . . . . . . 12 (Fun ◡𝑓 → (𝑓 “ (ω ∖ {∅})) = ((𝑓 “ ω) ∖ (𝑓 “ {∅})))
3516, 33, 343syl 19 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓 “ (ω ∖ {∅})) = ((𝑓 “ ω) ∖ (𝑓 “ {∅})))
36 f1fn 6809 . . . . . . . . . . . . . 14 (𝑓:ω⟶1-1𝐴 → 𝑓 Fn ω)
3736adantl 487 . . . . . . . . . . . . 13 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝑓 Fn ω)
38 fnima 6699 . . . . . . . . . . . . 13 (𝑓 Fn ω → (𝑓 “ ω) = ran 𝑓)
3937, 38syl 18 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓 “ ω) = ran 𝑓)
40 fnsnfv 6995 . . . . . . . . . . . . . 14 ((𝑓 Fn ω ∧ ∅ ∈ ω) → {(𝑓‘∅)} = (𝑓 “ {∅}))
4137, 9, 40sylancl 598 . . . . . . . . . . . . 13 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → {(𝑓‘∅)} = (𝑓 “ {∅}))
4241eqcomd 2769 . . . . . . . . . . . 12 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓 “ {∅}) = {(𝑓‘∅)})
4339, 42difeq12d 4067 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((𝑓 “ ω) ∖ (𝑓 “ {∅})) = (ran 𝑓 ∖ {(𝑓‘∅)}))
4435, 43eqtrd 2798 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓 “ (ω ∖ {∅})) = (ran 𝑓 ∖ {(𝑓‘∅)}))
4531, 44breqtrd 5137 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (ω ∖ {∅}) ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
46 entr 9071 . . . . . . . . 9 ((ω ≈ (ω ∖ {∅}) ∧ (ω ∖ {∅}) ≈ (ran 𝑓 ∖ {(𝑓‘∅)})) → ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
4724, 45, 46syl2anc 596 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
48 entr 9071 . . . . . . . 8 ((ran 𝑓 ≈ ω ∧ ω ≈ (ran 𝑓 ∖ {(𝑓‘∅)})) → ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
4919, 47, 48syl2anc 596 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}))
50 difexg 5298 . . . . . . . 8 (𝐴 ∈ V → (𝐴 ∖ ran 𝑓) ∈ V)
51 enrefg 9049 . . . . . . . 8 ((𝐴 ∖ ran 𝑓) ∈ V → (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓))
525, 50, 513syl 19 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓))
53 disjdif 4429 . . . . . . . 8 (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅
5453a1i 11 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅)
55 difss 4075 . . . . . . . . . 10 (ran 𝑓 ∖ {(𝑓‘∅)}) ⊆ ran 𝑓
56 ssrin 4141 . . . . . . . . . 10 ((ran 𝑓 ∖ {(𝑓‘∅)}) ⊆ ran 𝑓 → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)))
5755, 56ax-mp 5 . . . . . . . . 9 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓))
58 sseq0 4357 . . . . . . . . 9 ((((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) ⊆ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) ∧ (ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)
5957, 53, 58mp2an 705 . . . . . . . 8 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅
6059a1i 11 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)
61 unen 9111 . . . . . . 7 (((ran 𝑓 ≈ (ran 𝑓 ∖ {(𝑓‘∅)}) ∧ (𝐴 ∖ ran 𝑓) ≈ (𝐴 ∖ ran 𝑓)) ∧ ((ran 𝑓 ∩ (𝐴 ∖ ran 𝑓)) = ∅ ∧ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∩ (𝐴 ∖ ran 𝑓)) = ∅)) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) ≈ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)))
6249, 52, 54, 60, 61syl22anc 852 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) ≈ ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)))
638frnd 6748 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ran 𝑓 ⊆ 𝐴)
64 undif 4441 . . . . . . 7 (ran 𝑓 ⊆ 𝐴 ↔ (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) = 𝐴)
6563, 64sylib 221 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓)) = 𝐴)
66 uncom 4160 . . . . . . 7 ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)) = ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)}))
67 eldifn 4071 . . . . . . . . . . 11 ((𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓) → ¬ (𝑓‘∅) ∈ ran 𝑓)
68 fnfvelrn 7112 . . . . . . . . . . . 12 ((𝑓 Fn ω ∧ ∅ ∈ ω) → (𝑓‘∅) ∈ ran 𝑓)
6937, 9, 68sylancl 598 . . . . . . . . . . 11 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝑓‘∅) ∈ ran 𝑓)
7067, 69nsyl3 139 . . . . . . . . . 10 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ¬ (𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓))
71 disjsn 4673 . . . . . . . . . 10 (((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅ ↔ ¬ (𝑓‘∅) ∈ (𝐴 ∖ ran 𝑓))
7270, 71sylibr 237 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅)
73 undif4 4423 . . . . . . . . 9 (((𝐴 ∖ ran 𝑓) ∩ {(𝑓‘∅)}) = ∅ → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}))
7472, 73syl 18 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}))
75 uncom 4160 . . . . . . . . . 10 ((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) = (ran 𝑓 ∪ (𝐴 ∖ ran 𝑓))
7675, 65eqtrid 2810 . . . . . . . . 9 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) = 𝐴)
7776difeq1d 4065 . . . . . . . 8 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (((𝐴 ∖ ran 𝑓) ∪ ran 𝑓) ∖ {(𝑓‘∅)}) = (𝐴 ∖ {(𝑓‘∅)}))
7874, 77eqtrd 2798 . . . . . . 7 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((𝐴 ∖ ran 𝑓) ∪ (ran 𝑓 ∖ {(𝑓‘∅)})) = (𝐴 ∖ {(𝑓‘∅)}))
7966, 78eqtrid 2810 . . . . . 6 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → ((ran 𝑓 ∖ {(𝑓‘∅)}) ∪ (𝐴 ∖ ran 𝑓)) = (𝐴 ∖ {(𝑓‘∅)}))
8062, 65, 793brtr3d 5142 . . . . 5 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → 𝐴 ≈ (𝐴 ∖ {(𝑓‘∅)}))
8180ensymd 9070 . . . 4 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝐴 ∖ {(𝑓‘∅)}) ≈ 𝐴)
82 entr 9071 . . . 4 (((𝐴 ∖ {𝐵}) ≈ (𝐴 ∖ {(𝑓‘∅)}) ∧ (𝐴 ∖ {(𝑓‘∅)}) ≈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
8313, 81, 82syl2anc 596 . . 3 (((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑓:ω⟶1-1𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
842, 83exlimddv 1970 . 2 ((ω ≼ 𝐴 ∧ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
85 difsn 4763 . . . 4 (¬ 𝐵 ∈ 𝐴 → (𝐴 ∖ {𝐵}) = 𝐴)
8685adantl 487 . . 3 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) = 𝐴)
87 enrefg 9049 . . . . 5 (𝐴 ∈ V → 𝐴 ≈ 𝐴)
884, 87syl 18 . . . 4 (ω ≼ 𝐴 → 𝐴 ≈ 𝐴)
8988adantr 486 . . 3 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → 𝐴 ≈ 𝐴)
9086, 89eqbrtrd 5133 . 2 ((ω ≼ 𝐴 ∧ ¬ 𝐵 ∈ 𝐴) → (𝐴 ∖ {𝐵}) ≈ 𝐴)
9184, 90pm2.61dan 825 1 (ω ≼ 𝐴 → (𝐴 ∖ {𝐵}) ≈ 𝐴)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 401   = wceq 1570  ∃wex 1812   ∈ wcel 2147  Vcvv 3454   ⊆ wss 3900   ∖ cdif 4048   ∩ cin 4092   ∪ cun 4152  ∅c0 4281  {csn 4588   class class class wbr 5108  ◡ccnv 5657  ran crn 5659   ↾ cres 5660   “ cima 5661  Fun wfun 6560   Fn wfn 6561  ⟶wf 6562  ⟶1-1wf1 6563  ⟶1-1ontowf1o 6565  ‘cfv 6566  ωcom 7911   ≈ cen 9008   ≼ cdom 9009
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-10 2180  ax-11 2197  ax-12 2216  ax-ext 2735  ax-sep 5255  ax-nul 5266  ax-pow 5334  ax-pr 5398  ax-un 7783
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2102  df-mo 2567  df-eu 2597  df-clab 2742  df-cleq 2755  df-clel 2839  df-nfc 2913  df-ne 2960  df-ral 3081  df-rex 3091  df-rab 3417  df-v 3456  df-sbc 3743  df-csb 3852  df-ss 3901  df-pss 4017  df-dif 4050  df-in 4094  df-un 4154  df-nul 4282  df-if 4486  df-pw 4562  df-sn 4589  df-pr 4591  df-op 4841  df-uni 4873  df-br 5109  df-opab 5174  df-mpt 5193  df-tr 5219  df-id 5553  df-eprel 5558  df-po 5566  df-so 5567  df-fr 5611  df-we 5613  df-xp 5664  df-rel 5665  df-cnv 5666  df-co 5667  df-dm 5668  df-rn 5669  df-res 5670  df-ima 5671  df-ord 6391  df-on 6392  df-lim 6393  df-suc 6394  df-iota 6520  df-fun 6568  df-fn 6569  df-f 6570  df-f1 6571  df-fo 6572  df-f1o 6573  df-fv 6574  df-om 7912  df-er 8755  df-en 9012  df-dom 9013
This theorem is used by:  infdiffi  9696  infdju1  10307  infpss  10333  soinfdom  35841
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